Variable-speed gear transmission



April 23, 1946. 1-, BERRY ETAL 2,398,997

VARIABLE SE'EED GEAR TRANSMISSION Filed Feb. 22,- 1943 AUTO MAT);

CONTROL Invehtors: Theodore M. Berry, I I ,Alfred H Canada by fin 7? W M Their Attorney.

- Patented Apr. '23, 1946 U'NIITED s'r-A'ras' PATENT OFFICE Theodore M Berry, Schenectady, N. Y and Alfred H. Canada, Fort Belvoir 'va assignors to General Electric Company, a corporation of New York 4 7 Application February 22, 1943, Serial No. 476,664

other gears 22, 28.

operatively associated with gears 24, 25, 26 and 4 Claims. "(ct 74-472).-

The present invention relates to variable speed gear transmission including a driving shaft with g a plurality of gears thereon anddriven shaft means with gear cooperatively associated with the gears of the driving shaft together with means for shifting said gear to vary the speed ratio 'For a consideration of what we believe to be" novel and our invention, attentionis directed to the following description and the claims appended thereto in connection with the acco Denying drawing. l

The single figure of the drawing illustrates diatically an embodiment of our invention.

The arrangement in the present example includes two devices It and II arranged to be alternately driven by a motor I2 through a variable gear transmission mechanism l3. The gear transmission mechanism l3 comprises driven shaft means, in the present example two driven shaft l4 and I! with pinions l6 and I1 respectively meshing with gear l8 and 19 respectively. The gears l8 and is form part ofthe devices In and II respectively. The shaft l4 carries two 'other gears 28 and 2| and the shaft 15 carries two Thegears 20 to 23 are 21 secured to a hollow spindle or sleeve 28 axially the latter by a key 30. Thus the spindle 28 while 28. The ends of the cylinder 32 have supply ports 39 connected to a conduit 48 tor conducting fluid under pressure to both ends of the cylinder. The

I connection of the conduit 48 to the ports 39 in- J between the driving shaft and the driven shaft slidable' on a driving shaft 29 and connected to j slidable on the shaft 29 is positively driven by the latter. The shaft 29 is driven by a worm gear 8! from the shaft of the motor l2. In the position shown the driving gear 24 meshes with the driven gear 2% so that torque is transmitted from the motor l2 to the device It. When the spindle 28 is moved to the right the gears 20, 24

are disengaged and the driving or second gears 1 .and secured to a piston rod 35 connected at its right-hand end to an arm 36 carrying a roller I! between two collar 38 on the sleeve eludes-restrictions or orifices 40a. An intermediate portion of the cylinder wall is provided with a plurality of axially spaced outlet ports 4|, 4 2, 43

and 44. In the present example-there are four ports corresponding in spacing and number to the spacing and number of the different gear positions. Each port 4| to 44 is connected by a separate conduit or conduit branch 45 including a normally closed valve 46 to a conduit 41 with a bleed hole 48. The valves 46 are remote-controlled by solenoids 48 connected to a source of current supply 50 through pushbutton switches .SI, 52, 53, 54 respectively. In the position shown the piston 34 is in'alignment with or covers'the port 4|. The four valves 46 are in closed position, the solenoids 49 being deenergized. The fluid pressures on opposite sides of the piston 38 are balanced. If new the valve 46 associated with the port 42 isopened by closing the pushbutton '52, fluid under pressure is discharged from the right-hand s de of the piston 34 through conduit 41 and the bleed hole 48. Thi causes unbalance of pressure on opposite sides of the piston, resulting in movement of-the piston 34 towards the right until the piston covers the port 42. Upon movement of the piston 34 into line with the port 42 the driving gear 25 is brought into mesh with the driven gear 2|. If thereafter the pushbutton 54 is closed the piston 34 is moved further to the right into alignment with the port 44, thus effecting engagement between the driving gear 21 and the driven. gear 28. The switches 5| to 54 maybe electrically interlocked in known manner so that only one can be closed at one time.

In case the driving gears are normally rotated at high speed it is desirable to reduce the speed and to effect the gear shifting at low speed of the driving gears. Such slow speed facilitates the meshing of the driving gears with the corresponding driven gears. Inthe present example the motor l2 during normal operation is connected to-the line 68 through-a circuit including a conductor 85, an automatic control 58, a conductor 51 including a contact member 58 nonnallybiased towards closing position by a spring 69 and a conductor Bil-connected to one side of the line 50 and another conductor 8! connecting the motor 12 directly to the other side of the line 50. According t6 our invention we provide. means for automatically rendering the automatic control 56 inoperative and for connecting the motor 12 through a resistor to the line 59 during the gear shift operation. This is accomplished by the provision of means including a pressure responsive device 62 having a bellows secured at its left-hand end to a support 63 and connected by a pipe 64 to the conduit 41. The right-hand end of the bellows i's connected by a rod 65 to the contactmaking member 58 to eifect opening of the latter upon a certain increase in pressure in the conduit Al. The spindle 65 carries another contactmaking member 66 for closing contacts 61 to con-Q nect the motor i2 to the line 50 through a resistor 92' Assuming that the bleed hole 48 discharges to atmosphere, the pressure in the conduit ll i normally atmospheric pressure. If now one of th valve for controlling the ports 42, 43, M is opened, fluid under pressure is discharged from the right-hand end of the cylinder 32,, causing movement of the piston 35 to the right in the manner described above. The discharge of fluid under pressure causes increase in pressure in the conduit 41 and through the pipe 64 in the bellows 82 whereby the latter expand and causes opening movement of the contact-making member 58 and closing of the contact 6'! by the contact-making member 66, thus connecting the motor 12 to the line 50 through the resistor 68 to slowly rotate the motor l2 during the gear shift operation. In order to assure an increase in pressure in the bellows 62 to cause expansion of the latter upon opening of one of the valves the hole or restriction 48 is preferably made of a size slightly smaller than the restrictions is in the charge ports and means for rotating the second gears at a predetermined speed upon opening of one of the valved conduits.

2. Variable speed gear transmission comprising driven shaft means with a plurality of first gears thereon, a driving shaft with a plurality of second gears thereon each for cooperation with one of the first gears, and means for shifting the second Sears to vary the speed ratio between the driven shaft means and the driving shaft, a. hydraulic motor for shifting the second gears, said motor having a cylinder with supply ports at the ends and axially spaced discharge port at an intermediate portion thereof, a piston slidably disposed in the cylinder and connected to the second gears, means for continuously conducting fluid under pressure to the supply ports, conduit means connected to the outlet ports including a valve for each port, remote control mean selectively, to open any one of the valves to effect movement of the piston into alignment with a particular port and means for rotating the driv-.

' ing shaft at a predetermined speed upon openconduit). Thus the supp y of fluid under pressure through the conduit 40 to th cylinder will be sufficient to effect an increase in pressure in the pipe 64 and the bellow 62 communicating therewith upon opening of one of the valves 46. The contacts 61 remain closed until the piston 34 has reached its new position whereupon the pressure in the conduit 41 drops to atmospheric pressure, resulting in opening of the contacts 61 and reclosing of the normal operating circuit of the motor l2. Thu during gear shifting operation the speed of the motor I2 is automatically reduced and upon completion of the gearshifting the motor assumes its normal operation.

What we claim a new and desire to secure by Letters Patent of the United States is:

1. Variable speed gear transmission comprising driven shaft means with a plurality of spaced first gears, a driving shaft with a plurality of axially spaced second gears connected thereto,

and means for shifting the second gears into different positions to vary the' speed ratio between the driving shaft and the driven shaft means, said shifting meansincluding a hydraulic motor having a cylinder with an admission port for fluid under pressure at each endi a plurality of axially spaced discharge ports in an intermediate portion of the cylinder, 3 piston slidably disposed in the cylinder having a stem connected to the second gears, a source of fluid under Dressure normally communicating with said ports, separate valved conduits connected to said dis-.

ing of one of the valves to facilitate meshing engagement between the first and second gears.

3. Variable speed gear transmission comprising a driven shaft with a plurality of first gears thereon, a driving shaft, a motor for the driving shaft, means including a sleeve with a plurality of second gears secured thereto and axially movable on the driving shaft to transmit torque between the driving shaft and the driven shaft at difierent speed ratios, a hydraulic motor having a cylinder with supply ports at it ends and a plurality of axially spaced discharge ports at an intermediate portion, a piston movable in the cylinder and connected to said sleeve, a. conduit having a plurality of branches each with a normally closed valve and connectedto one of the outlet ports, and means for selectively Opening any one of said valves and simultaneously causing the motor to rotate at low speed.

4. Variable speed gear transmission comprising a driven shaft with a plurality of first gears thereon, a drive shaft, a motor for the drive shaft, means including a sleeve with a plurality of second gears secured thereto and axially movable on the drive shaft to transmit torque between the drive shaft and the driven shaft at different speed ratios, a hydraulic motor having a cylinder with fluid pressure supply ports at its ends and a plurality of axially spaced discharge ports at an intermediate portion, a piston movable in the cylinder and connected to said sleeve, a conduit with a'bleed hole having a plurality of branches each with a normally closed valve and connected to THEODORE M'. BERRY. ALFRED H. CANADA. 

